Asymmetric tibial components for a knee prosthesis

A tibial-prosthesis baseplate comprising:

• a distal surface comprising a bone-contacting surface;
• a proximal surface comprising a tibial bearing engagement surface generally opposite the distal surface, the proximal surface having a lateral compartment and a medial compartment;
• a peripheral wall extending between the distal surface and the proximal surface and defining a periphery of the tibial baseplate;
• an anteroposterior axis dividing the proximal surface and the periphery into the medial compartment and the lateral compartment;
• and
• a centroid defined by the periphery of the tibial baseplate, the centroid medially biased with respect to the anteroposterior axis;
• wherein the periphery includes:
• an anterior edge and a lateral posterior edge generally opposite the anterior edge and forming a posterior boundary of the lateral compartment, the lateral compartment defining a lateral anteroposterior extent (DAPL) extending from the anterior edge of the periphery to the lateral posterior edge thereof;
• and
• a medial posterior edge generally opposite the anterior edge and forming a posterior boundary of the medial compartment, the medial compartment defining a medial anteroposterior extent (DAPM) extending from the anterior edge of the periphery to the medial posterior edge thereof;
• wherein the DAPM is larger than the DAPL;
• wherein a posterior-medial distance (DMP) extends from the centroid toward a posterior-medial corner arc of the periphery at an angle of 130 counter-clockwise degrees from the anteroposterior axis and a posterior-lateral distance (DLP) extends from the centroid toward a posterior-lateral corner arc of the periphery at an angle of 120 clockwise degrees from the anteroposterior axis, and wherein the DMP is larger than the DLP for a given size of the tibial baseplate.

A tibial baseplate comprising:

• a distal surface comprising a bone-contacting surface;
• a proximal surface comprising a tibial bearing engagement surface generally opposite the distal surface, the proximal surface having a lateral compartment and a medial compartment;
• a peripheral wall extending between the distal surface and the proximal surface and defining a periphery of the tibial baseplate;
• and
• an anteroposterior axis dividing the proximal surface and the periphery into the medial compartment and the lateral compartment;
• and
• a centroid defined by the periphery of the tibial baseplate, the centroid medially biased with respect to the anteroposterior axis;
• wherein the medial compartment of the proximal surface has a medial surface area (SAM) and the lateral compartment of the proximal surface has a lateral surface area (SAL), and wherein the SAM is larger than the SAL;
• wherein a posterior-medial distance (DMP) extends from the centroid toward a posterior-medial corner arc of the periphery at an angle of 130 counter-clockwise degrees from the anteroposterior axis and a posterior-lateral distance (DLP) extends from the centroid toward a posterior-lateral corner arc of the periphery at an angle of 120 clockwise degrees from the anteroposterior axis, and wherein the DMP is larger than the DLP for a given size of the tibial baseplate.